ESSE 2220 – Lab 1 Report¶
Course: ESSE 2220
Lab Title: Raspberry Pi LED Morse Code
Date Performed: 2025-09-12
Date Submitted: 2025-09-12
1. Names & Group Info¶
Group Number: GROUP 5
Members: Yathharthha Kaushal · Owen Oliver
2. Circuit Setup¶
GPIO Pin Used for LED: GPIO 26
We connected the LED (with resistor) to pin 26 and ground so the Raspberry Pi could control it through Python.
Schematic / Wiring Notes:
- Anode (long leg) → Series resistor (212 Ω) → GPIO pin.
- Cathode (short leg) → Ground (GND).
- We used BCM because it is less hardware dependent, and works across different pi's as well (so if this program is ever to be used later on a different device, it will likely work).
3. Code (with Comments)¶
In [ ]:
import RPi.GPIO as GPIO #type: ignore
import time
GPIO.setmode(GPIO.BCM)
# Global Variables / Data
studentNumbers = ["221116678", "221430194"]
unit = 0.2
shortDelay = 1*unit
longDelay = 3*unit
varDelay = 7*unit
LED_PIN = 26 # Define LED pin globally
# Morse code dictionary for alphanumeric characters (uses map and key concept from Java course)
MORSE_CODE = {
'A': '.-', 'B': '-...', 'C': '-.-.', 'D': '-..', 'E': '.', 'F': '..-.',
'G': '--.', 'H': '....', 'I': '..', 'J': '.---', 'K': '-.-', 'L': '.-..',
'M': '--', 'N': '-.', 'O': '---', 'P': '.--.', 'Q': '--.-', 'R': '.-.',
'S': '...', 'T': '-', 'U': '..-', 'V': '...-', 'W': '.--', 'X': '-..-',
'Y': '-.--', 'Z': '--..',
'0': '-----', '1': '.----', '2': '..---', '3': '...--', '4': '....-',
'5': '.....', '6': '-....', '7': '--...', '8': '---..', '9': '----.',
' ': ' ' # Space between words
}
"""Setup function to configure GPIO pins"""
def setup():
# Configure the LED pin as output
GPIO.setup(LED_PIN, GPIO.OUT)
"""Convert student numbers to Morse code"""
def convertDataToMorse():
morseArr = []
for studentNumber in studentNumbers:
morse_string = ""
for char in studentNumber:
if char.upper() in MORSE_CODE:
morse_string += MORSE_CODE[char.upper()] + " " # Add space between characters
morseArr.append(morse_string.strip()) # Remove trailing space
return morseArr
"""Functions to control the LED pin"""
def pinOn(duration):
GPIO.output(LED_PIN, GPIO.HIGH) #type: ignore
time.sleep(duration)
GPIO.output(LED_PIN, GPIO.LOW) #type: ignore
"""Turn off the pin for a specified duration"""
def pinOff(duration):
GPIO.output(LED_PIN, GPIO.LOW) # type: ignore
time.sleep(duration)
"""Drive the Morse code to blinks on the LED"""
def driveMorseToBlinks(morseInputArr):
for i, morseInput in enumerate(morseInputArr):
print(f"Playing student number {i+1}: {studentNumbers[i]} -> {morseInput}")
for c in list(morseInput):
if c == '.':
pinOn(shortDelay)
pinOff(shortDelay) # Short delay after dot
elif c == '-':
pinOn(longDelay)
pinOff(shortDelay) # Short delay after dash
elif c == ' ':
pinOff(longDelay) # Space between characters (no additional delay needed)
# Add delay between different student numbers
if i < len(morseInputArr):
print("Delay between student numbers...")
pinOff(varDelay)
def destroy():
GPIO.cleanup()
if __name__ == '__main__': # Program entrance
setup()
try:
while True:
driveMorseToBlinks(convertDataToMorse())
except KeyboardInterrupt: # Handle Ctrl+C gracefully
print("\nProgram interrupted by user")
except Exception as e: # Handle other exceptions
print(f"An error occurred: {e}")
finally:
destroy()
4. Logic Explanation (Step-by-Step)¶
Our program implements Morse code transmission using a Raspberry Pi's GPIO to control an LED, following these steps:
- We store Morse code patterns in a dictionary for all alphanumeric characters, with timing based on a 0.2s unit (dots = 1 unit, dashes = 3 units).
- The program hardcodes two student ID numbers in the
studentNumbersarray and initializes the LED pin (GPIO 26) as an output. - For each student number, the
convertDataToMorse()function translates each digit into its corresponding Morse sequence (dots/dashes with spaces). - The
driveMorseToBlinks()function processes each Morse character: blinking the LED briefly for dots (0.2s), longer for dashes (0.6s), with appropriate pauses between elements. - The program prints the current student number and its Morse representation to the terminal before blinking, with a longer delay (1.4s) between transmitting different student numbers.
- The main loop continuously cycles through all student numbers until interrupted, and the
destroy()function ensures GPIO resources are properly released when the program exits.
5. Output (Run Evidence)¶
5.1 Terminal Output¶
log
Playing student number 1: 221116678 -> ..--- ..--- .---- .---- .---- -.... -.... --... ---..
Delay between student numbers...
Playing student number 2: 221430194 -> ..--- ..--- .---- ....- ...-- ----- .---- ----. ....-
Delay between student numbers...
Playing student number 1: 221116678 -> ..--- ..--- .---- .---- .---- -.... -.... --... ---..
5.2 Photo of Physical Circuit¶
